This invention relates to an electromagnetic valve in a security device for fuel, such as natural gas, propane or the like, in which an electromagnetic valve circuit is used to open and close a pipe through which fuel flows. The circuit is made up of an attracting circuit and an attraction holding circuit.
The performance of an electromagnetic valve is as shown in FIG. 1; that is, when the electromagnetic valve carries out the attraction phase, it requires a large attracting current I.sub.O according to the valve stroke; however, after being attracted, the electromagnetic valve can be maintained attracted with a small attraction holding current I.sub.M. In a conventional electromagnetic valve operating method, current for attraction is allowed to flow in the electromagnetic valve at all times. Therefore, the conventional electromagnetic valve operating technique is disadvantageous in that current is consumed wastefully where the electromagnetic valve is placed in the attraction state for a long period of time.
Accordingly, in view of the above-described difficulties accompanying the conventional method, an object of this invention is to provide an electromagnetic valve in a security device for fuel, in which no wasteful current consumption is caused when the electromagnetic valve is maintained open by applying current thereto for a long period of time.
Another object of this invention is to provide an electromagnetic valve circuit in a security device for fuel that eliminates the generation of heat when the reset switch is closed erroneously such that the electromagnetic valve coil draws a large attracting current.
Still another object of this invention is to provide for a valve circuit that minimizes power consumption.
An important aspect of this invention resides in a circuit for an electrogmagnetic valve that is made up of an attracting circuit and an attraction holding circuit. The attracting circuit is connected in parallel to the attraction holding circuit through an attracting switch which is closed only when the attraction is effectuated.